8 



strongly marked in the Ursine Dasyure, or Devil of the Tasmanian 

 colonists, the largest existing species of the genus, and a most 

 pestilent animal in the poultry yard or larder. 



Genus Phascogale. 

 Incisors ^; canines J-^| ; praemolares |^ ; molares ^ : = 46. 



In the present dental formula may be discerned a step in the 

 transition from the Dasyures to the Opossums, not only in the in- 

 creased number of spurious molares, but also in shape and pro- 

 portions of the incisors. In the upper jaw the two middle in- 

 cisors are longer than the rest, and separated from them by a 

 brief interval ; they are more curved and project more forward. 

 The three lateral incisors diminish in size to the outermost. The 

 middle incisors of the lower jaw also exceed the lateral ones in 

 size, and project beyond them but not in the same degree, nor are 

 they separated from them by an inter\-al as in the upper jaw. The 

 canines are relatively smaller than in the DasjTires. The spurious 

 molares present a similar form, but the third is much smaller and sim- 

 pler than the two preceding ones. The true molares resemble in 

 their structure those of the Dasyures. The general character of 

 the dentition of these small Marsupials approximates to the insecti- 

 vorous type in the Shrew, Hedgehog, &c., among the placental 

 Mammalia ; and corresponds with the food and habits of the species 

 which thus lead from the Zoophagous to the Entomophagous tribe. 



Other hnks which once bound these tribes more closely together 

 are now lost, and are indicated only by the few fossil remains 

 which have rendered the Stonesfield oolite so celebrated. One of 

 these extinct genera, which I have called Phascolotherium, presents 

 the same numerical formula, apparently, as in the Thylacinus 

 and Phascogale ; but, if another incisor existed in each ramus of 

 the lower jaw, as seems to be indicated by the fossil, then the den- 

 tition will agree with that of the genus Didelphis. 



Incisors ^ ; canines j^j ; praemolares ^^ ; molares ^—^. 



or 



4 — 1 



The incisors and canines are separated by vacant interspaces, 

 and occupy a large proportion of the dental series : the true mo- 

 lares resemble those of Thylacinus. 



Tribe II. ENTOMOPHAGA. 



Tills Is the most extensive and varied of the primary groups of 

 the Marsupial order. In the system of Cuvier, the species of this 

 tribe are united with those of the preceding to form a single group 

 characterized by the presence of long canines and small incisors in 

 both jaws ; but in most of the Entomophagous genera of the pre- 

 sent classification, the canines present a marked inferiority of de- 

 velopment, and the species are consequently unable to cope with 

 animals of their own size and grade of organization, but prey upon the 

 smaller and weaker classes of invertebrate animals. Their intestinal 



